This invention relates generally to turbine nozzle assemblies and specifically, to platform interface configurations for stage 2 CMC nozzle vanes.
Sealing between high temperature components such as ceramic matrix composite (CMC) nozzle vanes and radially inner and outer metallic attachments or platforms creates problems relating to steep thermal gradients with associated high thermal stresses and reduced component life; internal pressure due to cooling air resulting in air flow wall distortion; and time varying performance erosion due to historical seal degradation. Eliminating the seal between a CMC vane and metal inner and outer platforms, however, results in an open channel for hot gas ingestion. Accordingly, there remains a need for a new geometry at the interface of the CMC vane and either one or both of the radially inner and outer metallic platforms that accommodates the inherent difficulties in the matching of ceramic and metal components, and that also eliminates the need for separate and discrete sealing elements. Seal-less design is also synonymous with unpressurized vane design.